CN115179445B - CNC (computer numerical control) processing method for vacuum cavity sealing piece based on space positioning error model - Google Patents
CNC (computer numerical control) processing method for vacuum cavity sealing piece based on space positioning error model Download PDFInfo
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Abstract
The invention discloses a CNC processing method of a vacuum cavity sealing piece based on a space positioning error model, which comprises the following steps: s1, constructing a space positioning error model of a workpiece based on a multi-body system theory; s2, identifying geometric errors of the rotating shaft through a laser interferometer; s3, decomposing the space positioning error; s4, constructing a compensation data model of the space positioning error; s5, performing compensation quality control on the correction coefficient based on a second-generation non-dominant sorting genetic algorithm; s6, starting a range finder to calculate the distance between the machining tool and the workpiece; s7, the controller controls the clamp to slide to a designated position; s8, detecting a linkage track of the rotating shaft according to a preset period; s9, updating the geometric error correction data to an error database regularly. The multi-body system theory obtained through abstraction of the numerical control machine tool machining center can construct an accurate space positioning error model without being limited by the structure and the motion complexity, and the machining precision of the sealing element is greatly improved.
Description
Technical Field
The invention relates to the technical field of vacuum cavity sealing piece machining, in particular to a CNC machining method for a vacuum cavity sealing piece based on a space positioning error model.
Background
With the continuous progress of society, new materials, automation, computer and other scientific technologies have achieved breakthrough results, and the machine manufacturing industry has accordingly made historic changes, and has rapidly developed towards high efficiency, high precision and high intelligence.
The atmosphere in which we live is filled with a large amount of nitrogen, oxygen and other various gas molecules, and when these gas molecules move to the surface of the object, a part of them adhere to the surface of the object. This does not affect how much in daily life, but these subtle changes cause various troubles in the production process of semiconductor devices requiring extremely high environmental demands. Semiconductor devices comprise a plurality of layers of various materials that, if mixed with gaseous molecules between the layers of different materials, can destroy the electrical or optical properties of the device. Therefore, the higher the vacuum degree in the production process, the better the performance of the manufactured semiconductor device.
The vacuum system is an air extraction system for ensuring that the reaction cavity of the vacuum system obtains the vacuum pressure required by the process, and is a decisive factor for meeting the specific pressure condition required by the semiconductor manufacturing process, so that the performance optimization of the vacuum system is still an important means for improving the semiconductor manufacturing technology.
Along with industrial development and discipline fusion, the application scene of the vacuum technology is greatly enriched, and the digitization and intelligent degree of related products and scientific instruments are obviously improved; the application conditions of the technological front and the emerging fields are more severe, and the technical attack difficulty and risk are obviously increased. The vacuum cavity is used as one of the basic components of the vacuum technology, the improvement of the manufacturing level and the process optimization of the vacuum cavity become important supports for the construction of important scientific devices and the development of high-end equipment, and represent the development direction of the industrial basic commonality technology. The vacuum cavity is used as one of important parts in a semiconductor equipment system, and needs to meet the application conditions of complicated structure modeling, high and low temperature circulation, ultrahigh pressure, high vacuum circulation, irradiation damage, high temperature ablation, gravel erosion, chemical corrosion and the like, and the tightness of the vacuum cavity has a decisive influence on the performance of semiconductor devices.
The accuracy in the machining process determines the excellent degree of the sealing performance of the sealing element, the processes of high-automation intelligent conveying, detection, cutter machining and the like are realized in the CNC machining process of the metal sealing element at present, the machining accuracy degree is ensured through a numerical control system, but due to certain abrasion and deviation of a numerical control machine tool and various equipment in operation, a plurality of errors still exist in the long-term machining process, the sealing performance of the sealing element is influenced, and finally the performance of a vacuum cavity is influenced. Therefore, it is necessary to further improve the accuracy and efficiency of error detection in the numerical control system, and ensure the performance of the sealing member and the vacuum chamber.
Patent number CN106842922B discloses a numerical control machining error optimization method, which comprehensively considers a plurality of factors influencing numerical control machining, predicts machining state characteristic parameters and machining errors by using a mathematical fitting principle and a neural network model, carries out partial fine adjustment on a numerical control program according to the obtained prediction errors, and directly compensates the machining errors, thereby achieving the aim of optimizing the numerical control machining errors. However, the method still has certain defects that the position of a processing mechanism such as a machine tool of a processing center is not limited, and the processing in the processing process is positioned with high precision.
For the problems in the related art, no effective solution has been proposed at present.
Disclosure of Invention
Aiming at the problems in the related art, the invention provides a CNC processing method for a vacuum cavity sealing member based on a space positioning error model, so as to overcome the technical problems in the prior art.
For this purpose, the invention adopts the following specific technical scheme:
CNC machining method for vacuum cavity sealing piece based on space positioning error model comprises the following steps:
s1, constructing a space positioning error model of a workpiece based on a multi-body system theory;
s2, identifying geometric errors of the rotating shaft through a laser interferometer to form an error database;
s3, decomposing the space positioning error;
s4, combining a sag error compensation function of the numerical control system to construct a compensation data model of the space positioning error;
s5, compensating quality control is carried out on the correction coefficient based on a second-generation non-dominant sorting genetic algorithm, and optimization of the correction coefficient is achieved;
s6, starting a range finder to calculate the distance between the machining tool and the workpiece, and outputting a current position signal of the workpiece by combining the optimized correction coefficient;
s7, the controller controls the clamp to slide to a designated position, and a machining tool is used for precisely machining a workpiece;
s8, detecting a linkage track of the rotating shaft according to a preset period, setting a linkage track positioning error threshold value, and detecting the machining precision of the workpiece;
s9, updating the geometric error correction data to an error database regularly.
Further, the method for constructing the spatial positioning error model of the workpiece based on the multi-body system theory comprises the following steps:
s11, abstracting a mechanical system of a machining center into a multi-body system;
s12, constructing a topological graph and a low-order body array description body-body association relation;
s13, establishing a sub-coordinate system fixed on the body for each body, and describing the pose between the bodies according to the pose relation between the sub-coordinate systems;
s14, utilizing a 4x4 order D-H matrix to realize coordinate transformation of points in space among all sub-coordinate systems;
s15, constructing an actual pose matrix between two adjacent bodies according to the feature matrices of the two adjacent bodies;
s16, constructing pose matrixes of any two bodies;
s16, constructing an ideal coordinate array and an actual coordinate matrix of a machining tool tip center point in a machining tool body sub-coordinate system in the machining center;
s17, constructing a spatial error model of the machining center by utilizing the difference value between the ideal coordinate and the actual coordinate of the center point of the tip of the machining tool.
Further, the expression of the spatial error model is:
wherein e represents a spatial error model;
P wS representing an ideal coordinate array of a machining tool tip center point P in an S coordinate system;
P′ wS representing the actual coordinate array of the center point P of the tip of the machining tool in the S coordinate system, and
T SJ representing pose matrixes of an S coordinate system and a J coordinate system;
P tJ representing an ideal coordinate array of a machining tool tip center point P in a J coordinate system;
l represents the displacement amount, and n represents the number of sub-coordinate systems.
4, identifying the geometric error of the rotating shaft by a laser interferometer to form an error database, wherein the method comprises the following steps:
s21, mounting a double-frequency laser interferometer in the direction of a coordinate axis of a machine tool to be measured;
s22, adjusting the laser head to enable the measuring axis to coincide with or be parallel to the displacement axis of the machine tool, and pre-aligning the light path;
s23, inputting measurement parameters after laser preheating, and moving the machine tool for measurement according to a preset measurement program;
s24, identifying geometric errors in a working section of the numerical control machine tool by adopting a nine-line method;
s25, synthesizing various geometric error data to construct an error database.
Further, the identification of geometric errors in the working section of the digital machine tool by adopting the nine-line method comprises the following steps:
s241, establishing a workbench coordinate model, and setting a point A (X i ，Y i ，Z i )；
S242, when the fixed point A moves along the X-axis coordinate, measuring an X-direction movement error value, wherein the expression comprises:
represented by matrix, let
{δ x }＝[δ x (x) δ y (x) δ z (x) ε x (x) ε y (x) ε z (x)] T Then
{Δ(X)}＝[E x ]{δ x }
Wherein { delta } x -represents a set of x-direction errors;
x (x) Representing a linear displacement error;
y (x) And delta z (x) Respectively representing straightness errors in the y direction and the z direction;
ε x (x) Representing a roll error;
ε y (x) Representing pitch error;
ε z (x) Representing yaw error;
E x representing a coefficient matrix;
x, Y, Z the X-axis, Y-axis, Z-axis in the coordinate system, respectively;
X i 、Y i 、Z i coordinate values respectively representing the point a;
i represents that the value of the number of the coordinate axes is (1, 2, 3);
t represents matrix transposition;
s243, when the fixed point A moves along the Y-axis coordinate, measuring a Y-direction movement error value;
s244, when the fixed point A moves along the Z-axis coordinate, measuring a Z-direction movement error value;
s245, calculating the perpendicularity error by using the straightness error of each axis.
Further, the spatial positioning error is decomposed into a linear correlation and a nonlinear correlation.
Further, the method for constructing the spatial positioning error compensation data model by combining the sag error compensation function of the numerical control system comprises the following steps:
s41, correcting an ideal numerical control instruction by combining a linear related space positioning error;
s42, downloading the corrected ideal numerical control instruction to each controller, and outputting a cutter route;
s43, moving the processing cutter to a processing point according to the cutter route;
s44, constructing an actual movement route of the machining tool in a body coordinate system, and drawing a tool path;
s45, checking the tool path and the tool path, constructing a compensation data model of the space positioning error, and outputting a correction coefficient.
Further, the compensation quality control is performed on the correction coefficient based on the second-generation non-dominant sorting genetic algorithm to realize the optimization of the correction coefficient, and the method comprises the following steps:
s51, setting algorithm parameters and correction coefficient variation ranges;
s52, coding the machining center controller, and initializing a plurality of controller prevention schemes meeting constraints to form a population;
s53, calculating the time delay from the average processing tool to the controller, the time delay between the maximum controllers, the failure proportion of the average control path and the number of slave controllers of the average processing tool corresponding to each individual according to a preset data model and an objective function;
s54, performing non-dominant solution sequencing on the current population, and respectively calculating the crowding distance of individuals in each layer;
s55, selecting, crossing and mutating the population to generate a child population;
s56, merging the parent population and the offspring population according to elite retention strategy to obtain a next generation population;
s57, if the iteration number reaches the maximum iteration number, stopping iteration and outputting the optimal correction coefficient.
Further, the expression of the objective function is:
minF(CP)＝[f 1 (CP),f 2 (CP),f 3 (CP),-f 4 (CP)]
where minF (CP) represents the value of the objective function;
f 1 (CP) represents minimizing the time of the machining tool to the controllerExtending;
f 2 (CP) means minimizing the time delay between controllers;
f 3 (CP) means minimizing a control path failure rate;
f 4 (CP) means maximizing the average machining tool possession slave controller number;
CP denotes a deployment scenario of the controller.
Further, the calculation formula of the congestion distance includes:
wherein I (d) K ) Representing a crowding distance;
I(d 0 ) Representing an initial congestion distance;
i (k) m represents the value of the mth objective function of the kth individual in I;
m represents the number of objective functions.
The beneficial effects of the invention are as follows: the multi-body system theory obtained through abstraction of the numerical control machine tool machining center can construct an accurate space positioning error model without being limited by the structure and the motion complexity, and high-precision calculation, analysis, detection, compensation and control are carried out on the machining error of the machine tool; geometric error identification by matching with a laser interferometer and a nine-wire method is carried out, so that the detection precision and the identification efficiency of the error are greatly improved, the numerical control machining precision is further improved, and the vacuum cavity is ensured to have good sealing performance.
The invention integrates a second-generation non-dominant sorting genetic algorithm to carry out compensation quality control on the correction coefficient, and can further test and optimize and improve the error correction, thereby improving the processing precision of the workpiece to a greater extent, and the response delay between the processing controller and the processing cutter and other equipment can be reduced by calculating and optimizing the time delay among the equipment, thereby improving the efficiency of numerical control processing;
in addition, the invention has universality, is also suitable for the production and processing of other high-precision parts, plays a positive role in improving the product quality, improving the production efficiency, reducing the production cost and the like, and therefore, brings more social and economic benefits and has good market prospect.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a vacuum cavity seal CNC machining method based on a spatial positioning error model according to an embodiment of the present invention.
Detailed Description
According to an embodiment of the invention, a CNC machining method for a vacuum cavity sealing piece based on a space positioning error model is provided.
The invention will be further described with reference to the accompanying drawings and detailed description, as shown in fig. 1, a vacuum cavity seal CNC machining method based on a spatial positioning error model according to an embodiment of the invention, the method comprises the following steps:
s1, constructing a space positioning error model of a workpiece based on a multi-body system theory;
the establishment of an accurate spatial error model of the machining center is the basis of error identification. At present, a plurality of methods such as a triangle geometry method, an error matrix method, a neural network method, a rigid body kinematics method, a multi-body system theory method and the like are available for establishing a space error model. However, only the multi-body system theory method comprehensively considers various influencing factors and coupling relations of complex system movement, solves the problems of accuracy, universality and automation of the spatial error modeling of the machining center, and other methods have certain limitations. Therefore, the invention is based on the theory of a multi-body system and uses the pose matrix to build a space error model of the processing center.
Wherein, step S1 comprises the following steps:
s11, abstracting a mechanical system of a machining center into a multi-body system;
s12, constructing a topological graph and a low-order body array description body-body association relation;
s13, establishing a sub-coordinate system fixed on the body for each body, and describing the pose between the bodies according to the pose relation between the sub-coordinate systems;
s14, utilizing a 4x4 order D-H matrix (Denavit-Hartenberg) to realize coordinate transformation of points in space among all sub-coordinate systems;
s15, constructing an actual pose matrix between two adjacent bodies according to the feature matrices of the two adjacent bodies;
s16, constructing pose matrixes of any two bodies;
s16, constructing an ideal coordinate array and an actual coordinate matrix of a machining tool tip center point in a machining tool body sub-coordinate system in the machining center;
s17, constructing a spatial error model of the machining center by utilizing the difference value between the ideal coordinate and the actual coordinate of the center point of the tip of the machining tool, wherein the expression is as follows:
wherein e represents a spatial error model;
P wS representing an ideal coordinate array of a machining tool tip center point P in an S coordinate system;
P′ wS representing the actual coordinate array of the center point P of the tip of the machining tool in the S coordinate system, and
T SJ representing pose matrixes of an S coordinate system and a J coordinate system;
P tJ representing an ideal coordinate array of a machining tool tip center point P in a J coordinate system;
l represents the displacement amount, and n represents the number of sub-coordinate systems.
S2, identifying geometric errors of the rotating shaft through a laser interferometer to form an error database;
for a three-axis spatial coordinate system, if an object moves along a certain coordinate axis, there are 6 degrees of freedom in its motion, then there are 6 geometric error components, namely a straightness error along 3 coordinate axes and a rotational error for 3 coordinate axes.
Wherein, step S2 includes the following steps:
s21, mounting a double-frequency laser interferometer in the direction of a coordinate axis of a machine tool to be measured;
s22, adjusting the laser head to enable the measuring axis to coincide with or be parallel to the displacement axis of the machine tool, and pre-aligning the light path;
s23, inputting measurement parameters after laser preheating, and moving the machine tool for measurement according to a preset measurement program;
s24, identifying geometric errors in a working section of the numerical control machine tool by adopting a nine-line method;
the numerical control machine tool error identification methods are 22-wire method, 15-wire method, 14-wire method, 9-wire method and the like, and the former methods have low measurement efficiency and difficult adjustment of a measurement light path, so that certain errors can be caused. 9, the modeling method of the line method identification method is simple, convenient and universal; during modeling, uncertain assumption conditions are eliminated; the difficulty of light path adjustment is reduced, the workload is reduced, and 21 geometric errors in the whole working interval of the numerical control machine tool can be accurately identified by adopting a 9-line method.
The method for identifying the geometric errors of the working section of the digital machine tool by adopting the nine-wire method comprises the following steps:
s241, establishing a workbench coordinate model, and setting a point A (X i ，Y i ，Z i )；
S242, when the fixed point A moves along the X-axis coordinate, measuring an X-direction movement error value, wherein the expression comprises:
represented by matrix, let
{δ x }＝[δ x (x) δ y (x) δ z (x) ε x (x) ε y (x) ε z (x)] T
Then
{Δ(X)}＝[E x ]{δ x }
Wherein { delta } x -represents a set of x-direction errors;
x (x) Representing a linear displacement error;
y (x) And delta z (x) Respectively representing straightness errors in the y direction and the z direction;
ε x (x) Representing a roll error;
ε y (x) Representing pitch error;
ε z (x) Representing yaw error;
E x representing a coefficient matrix;
x, Y, Z the X-axis, Y-axis, Z-axis in the coordinate system, respectively;
X i 、Y i 、Z i coordinate values respectively representing the point a;
i represents that the value of the number of the coordinate axes is (1, 2, 3);
t represents matrix transposition;
s243, when the fixed point A moves along the Y-axis coordinate, measuring a Y-direction movement error value;
s244, when the fixed point A moves along the Z-axis coordinate, measuring a Z-direction movement error value;
s245, calculating the perpendicularity error by using the straightness error of each axis.
S25, synthesizing various geometric error data to construct an error database.
S3, decomposing the space positioning error, and decomposing the space positioning error into linear correlation and nonlinear correlation.
S4, combining a sag error compensation function of the numerical control system to construct a compensation data model of the space positioning error;
the existing numerical control machine tool error compensation method mainly comprises hardware compensation and software compensation. Because of the inherent defects of hardware compensation, the invention adopts a software compensation method based on an error model to correct an ideal numerical control instruction, and drives a numerical control machine tool through the numerical control instruction value after correction, so that the center of the tool of the machine tool moves to a machining point accurately, and error compensation is realized.
Wherein, step S4 includes the following steps:
s41, correcting an ideal numerical control instruction by combining a linear related space positioning error;
s42, downloading the corrected ideal numerical control instruction to each controller, and outputting a cutter route;
s43, moving the processing cutter to a processing point according to the cutter route;
s44, constructing an actual movement route of the machining tool in a body coordinate system, and drawing a tool path;
s45, checking the tool path and the tool path, constructing a compensation data model of the space positioning error, and outputting a correction coefficient.
S5, compensating quality control is carried out on the correction coefficient based on a second-generation non-dominant sorting genetic algorithm (NSGA-II algorithm), and optimization of the correction coefficient is achieved;
wherein, step S5 includes the following steps:
s51, setting algorithm parameters and correction coefficient variation ranges;
s52, coding the machining center controller, and initializing a plurality of controller prevention schemes meeting constraints to form a population;
s53, calculating the time delay from the average processing tool to the controller, the time delay between the maximum controllers, the failure proportion of the average control path and the number of slave controllers of the average processing tool corresponding to each individual according to a preset data model and an objective function;
wherein, the expression of the objective function is:
minF(CP)＝[f 1 (CP),f 2 (CP),f 3 (CP),-f 4 (CP)]
where minF (CP) represents the value of the objective function;
f 1 (CP) means minimizing the time delay of the machining tool to the controller, expressed as:
f 2 (CP) represents minimizing the latency between controllers, expressed as:
f 3 (CP) represents a minimized control-path failure ratio, expressed as:
f 4 (CP) means maximizing the average machining tool possession slave controller number expressed as:
CP represents a deployment scenario for the controller;
i, j each represent the number of nodes;
c i a number representing a machining tool node in which the controller in the ith control domain is located;
c j a number indicating a machining tool node in which the controller in the jth control domain is located;
x ij =1 means that the master controller of the machining tool i is the controller c in the j-th control domain i Otherwise x ij ＝0；
y ij =1 denotes the controller c in the j-th control domain j Is the slave controller of the machining tool i, otherwise y ij ＝0；
e i Representing the number of control paths each network element is located on;
k represents the number and numbering of control domains in the network topology;
n represents the number of machining tools;
w represents the number of physical network elements including the processing tool and the link;
s represents the number of paths between controllers;
s54, performing non-dominant solution sequencing on the current population, and respectively calculating the crowding distance of individuals in each layer;
wherein, the calculation formula of the crowding distance comprises:
wherein I (d) K ) Representing a crowding distance;
I(d 0 ) Representing an initial congestion distance;
i (k) m represents the value of the mth objective function of the kth individual in I;
m represents the number of objective functions.
S55, selecting, crossing and mutating the population to generate a child population;
s56, merging the parent population and the offspring population according to elite retention strategy to obtain a next generation population;
s57, if the iteration number reaches the maximum iteration number, stopping iteration and outputting the optimal correction coefficient.
S6, starting a range finder to calculate the distance between the machining tool and the workpiece, and outputting a current position signal of the workpiece by combining the optimized correction coefficient;
s7, the controller controls the clamp to slide to a designated position, and a machining tool is used for precisely machining a workpiece;
s8, detecting a linkage track of the rotating shaft according to a preset period, setting a linkage track positioning error threshold value, and detecting the machining precision of the workpiece;
s9, updating the geometric error correction data to an error database regularly.
In summary, by means of the technical scheme, the multi-body system theory obtained through abstraction of the numerical control machine tool machining center can construct an accurate space positioning error model without being limited by the structure and the motion complexity, and high-precision calculation, analysis, detection, compensation and control of the machine tool machining error can be performed; geometric error identification by matching with a laser interferometer and a nine-wire method is carried out, so that the detection precision and the identification efficiency of the error are greatly improved, the numerical control machining precision is further improved, and the vacuum cavity is ensured to have good sealing performance.
The invention integrates a second-generation non-dominant sorting genetic algorithm to carry out compensation quality control on the correction coefficient, and can further test and optimize and improve the error correction, thereby improving the processing precision of the workpiece to a greater extent, and the response delay between the processing controller and the processing cutter and other equipment can be reduced by calculating and optimizing the time delay among the equipment, thereby improving the efficiency of numerical control processing;
in addition, the invention has universality, is also suitable for the production and processing of other high-precision parts, plays a positive role in improving the product quality, improving the production efficiency, reducing the production cost and the like, and therefore, brings more social and economic benefits and has good market prospect.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the invention.
Claims (7)
1. CNC machining method for vacuum cavity sealing piece based on space positioning error model is characterized by comprising the following steps:
s1, constructing a space positioning error model of a workpiece based on a multi-body system theory; the method for constructing the spatial positioning error model of the workpiece based on the multi-body system theory comprises the following steps:
s11, abstracting a mechanical system of a machining center into a multi-body system;
s12, constructing a topological graph and a low-order body array description body-body association relation;
s13, establishing a sub-coordinate system fixed on the body for each body, and describing the pose between the bodies according to the pose relation between the sub-coordinate systems;
s14, utilizing a 4x4 order D-H matrix to realize coordinate transformation of points in space among all sub-coordinate systems;
s15, constructing an actual pose matrix between two adjacent bodies according to the feature matrices of the two adjacent bodies;
s16, constructing pose matrixes of any two bodies;
s16, constructing an ideal coordinate array and an actual coordinate matrix of a machining tool tip center point in a machining tool body sub-coordinate system in the machining center;
s17, constructing a spatial error model of the machining center by utilizing the difference value between the ideal coordinate and the actual coordinate of the center point of the tip of the machining tool; the expression of the spatial error model is as follows:
wherein e represents a spatial error model;
P wS representing an ideal coordinate array of a machining tool tip center point P in an S coordinate system;
P′ wS representing the actual coordinate array of the center point P of the tip of the machining tool in the S coordinate system, and
T SJ representing pose matrixes of an S coordinate system and a J coordinate system;
P tJ representing an ideal coordinate array of a machining tool tip center point P in a J coordinate system;
l represents a displacement amount;
n represents the number of sub-coordinate systems;
s2, identifying geometric errors of the rotating shaft through a laser interferometer to form an error database;
s3, decomposing the space positioning error;
s4, combining a sag error compensation function of the numerical control system to construct a compensation data model of the space positioning error;
s5, compensating quality control is carried out on the correction coefficient based on a second-generation non-dominant sorting genetic algorithm, and optimization of the correction coefficient is achieved; which comprises the following steps:
s51, setting algorithm parameters and correction coefficient variation ranges;
s52, coding the machining center controller, and initializing a plurality of controller prevention schemes meeting constraints to form a population;
s53, calculating the time delay from the average processing tool to the controller, the time delay between the maximum controllers, the failure proportion of the average control path and the number of slave controllers of the average processing tool corresponding to each individual according to a preset data model and an objective function;
s54, performing non-dominant solution sequencing on the current population, and respectively calculating the crowding distance of individuals in each layer;
s55, selecting, crossing and mutating the population to generate a child population;
s56, merging the parent population and the offspring population according to elite retention strategy to obtain a next generation population;
s57, if the iteration number reaches the maximum iteration number, terminating the iteration and outputting an optimal correction coefficient;
s6, starting a range finder to calculate the distance between the machining tool and the workpiece, and outputting a current position signal of the workpiece by combining the optimized correction coefficient;
s7, the controller controls the clamp to slide to a designated position, and a machining tool is used for precisely machining a workpiece;
s8, detecting a linkage track of the rotating shaft according to a preset period, setting a linkage track positioning error threshold value, and detecting the machining precision of the workpiece;
s9, updating the geometric error correction data to an error database regularly.
2. The CNC processing method of vacuum cavity sealing member based on the space positioning error model according to claim 1, wherein the identifying the geometric error of the rotating shaft by the laser interferometer to form an error database comprises the following steps:
s21, mounting a double-frequency laser interferometer in the direction of a coordinate axis of a machine tool to be measured;
s22, adjusting the laser head to enable the measuring axis to coincide with or be parallel to the displacement axis of the machine tool, and pre-aligning the light path;
s23, inputting measurement parameters after laser preheating, and moving the machine tool for measurement according to a preset measurement program;
s24, identifying geometric errors in a working section of the numerical control machine tool by adopting a nine-line method;
s25, synthesizing various geometric error data to construct an error database.
3. The CNC machining method for vacuum cavity sealing members based on a spatial positioning error model according to claim 2, wherein the identification of geometric errors in the working section of the numerical control machine tool by using a nine-wire method comprises the following steps:
s241, establishing a workbench coordinate model, and setting a point A (X i ，Y i ，Z i )；
S242, when the fixed point A moves along the X-axis coordinate, measuring an X-direction movement error value, wherein the expression comprises:
represented by matrix, let
{δ x }＝[δ x (x) δ y (x) δ z (x) ε x (x) ε y (x) ε z (x)] T
Then
{Δ(X)}＝[E x ]{δ x }
Wherein { delta } x -represents a set of x-direction errors;
δ x (x) Representing a linear displacement error;
δ y (x) And delta z (x) Respectively representing straightness errors in the y direction and the z direction;
ε x (x) Representing a roll error;
ε y (x) Representing pitch error;
ε z (x) Representing yaw error;
E x representing a coefficient matrix;
x, Y, Z the X-axis, Y-axis, Z-axis in the coordinate system, respectively;
X i 、Y i 、Z i coordinate values respectively representing the point a;
i represents that the value of the number of the coordinate axes is (1, 2, 3);
t represents matrix transposition;
s243, when the fixed point A moves along the Y-axis coordinate, measuring a Y-direction movement error value;
s244, when the fixed point A moves along the Z-axis coordinate, measuring a Z-direction movement error value;
s245, calculating the perpendicularity error by using the straightness error of each axis.
4. The vacuum cavity seal CNC machining method based on the spatial positioning error model according to claim 1, wherein the spatial positioning error is decomposed into linear and nonlinear correlations.
5. The CNC processing method of vacuum cavity sealing members based on a spatial positioning error model according to claim 4, wherein the constructing a spatial positioning error compensation data model by combining a sag error compensation function of a numerical control system comprises the following steps:
s41, correcting an ideal numerical control instruction by combining a linear related space positioning error;
s42, downloading the corrected ideal numerical control instruction to each controller, and outputting a cutter route;
s43, moving the processing cutter to a processing point according to the cutter route;
s44, constructing an actual movement route of the machining tool in a body coordinate system, and drawing a tool path;
s45, checking the tool path and the tool path, constructing a compensation data model of the space positioning error, and outputting a correction coefficient.
6. The CNC machining method of vacuum cavity seals based on a spatial positioning error model according to claim 5, wherein the expression of the objective function is:
minF(CP)＝[f 1 (CP),f 2 (CP),f 3 (CP),-f 4 (CP)]
where minF (CP) represents the value of the objective function;
f 1 (CP) means minimizing the time delay of the machining tool to the controller;
f 2 (CP) means minimizing the time delay between controllers;
f 3 (CP) means minimizing a control path failure rate;
f 4 (CP) means maximizing the average machining tool possession slave controller number;
CP denotes a deployment scenario of the controller.
7. The CNC processing method of a vacuum chamber seal based on a spatial positioning error model according to claim 6, wherein the calculation formula of the crowding distance comprises:
wherein I (d) K ) Representing a crowding distance;
I(d 0 ) Representing an initial congestion distance;
i (k) m represents the value of the mth objective function of the kth individual in I;
m represents the number of objective functions.
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